Cable guide and method for producing the same

ABSTRACT

When a glass fiber cable emerging from a main channel ( 1 ) is guided into a domestic channel line ( 2 ), in order to prevent this glass fiber cable from unacceptably having an excessively small radius of curvature in the direction-changing area ( 6 ), and thus being damaged, and in order to ensure that the glass fiber cable ( 3 ) is in the correct position, this glass fiber cable ( 3 ) is guided in a rigid guide tube ( 7 ) whose longitudinal axis runs essentially along a cylindrical envelope surface in its central section ( 7 ′″). The rigid guide tube ( 7 ) is fixed in a pipe connecting stub ( 10 ) which can be widened elastically and thus, after insertion into the domestic channel line ( 2 ), rests on the wall thereof in a stressed manner, and is fixed in its position. That end of the guide tube ( 7 ) which projects into the domestic channel line ( 2 ) is connected via a sleeve ( 8 ) to a flexible pipe, tube ( 5 ) or the like. The glass fiber cable is passed from a switching box ( 4 ) via the rigid guide tube ( 7 ) and the flexible tube ( 5 ) to a building which is located on a piece of land and is connected to the domestic channel line ( 2 ).

BACKGROUND OF THE INVENTION FIELD OF THE INVENTION

The invention relates to a cable guide as claimed in theprecharacterizing clause of claim 1, and to a method for producing sucha cable guide.

It is known for sewage channels to be used for laying cable lines, sincethis results in the advantage that it is possible to largely avoiddigging work. For this purpose, cable racks or similar supportingdevices for the cables to be laid are mounted in the area of the arch ofthe main water channel, which generally has an egg-shaped profile. Themain cables used in this context are glass fiber cables which, when laidretrospectively, can transport large amounts of data.

DE 19920459 A1 discloses an apparatus by means of which an opticalwaveguide cable is supplied to a channel system via a vertical shaftwhich allows access to this channel system. In order to ensurecompliance with the minimum permissible cable bending ratio, this knownapparatus is provided with a flexible tubular sheath, which surroundsthe cable, in the direction-changing area from the shaft to the channelsystem. The cable end projecting out of the sheath is connected via aterminal to a clamping apparatus, with the clamping force being chosensuch that the bending radius is not less than the minimum permissiblebending radius. In order to ensure that the cable and the sheathsurrounding this cable do not project into the channel in thedirection-changing area, it is necessary to incline the transitionalpoint between the shaft wall and the channel wall, which necessitates aconsiderable additional labour cost in the channel through which thesewage flows, and causes undesirable damage to the channel wall, withthe risk of a leak being formed there. Furthermore, this removal ofmaterial from the channel wall adversely effects the static strength.

DE 29802655 U1 discloses a protection apparatus for optical waveguidecables, in which a direction-changing element which has a groove thatholds the cable is provided in the direction-changing area between thewall of a vertical inspection shaft and the channel wall. Although noprovision is made in this known design to incline the corner which theshaft wall forms with the channel, the direction-changing element does,however, project well into the shaft, as a consequence of the curvaturethat is required to comply with the minimum permissible cable bendingradius. No such design is feasible in the opening of a domestic channelline into a main channel since floating material carried by thecontaminated water will become attached to the direction-changingelement there, thus not only resulting in a risk of damage to the cable,but also the possibility of partial blocking of the channel crosssection.

When cable lines are being laid to pieces of land with premisesrequiring connections to the cable network, via a domestic channel linewhich branches off from a main channel, opens approximately at rightangles into the main channel and has a maximum diameter of only 500 mm,or frequently even less, the radius of curvature must not be less than aspecific minimum radius of curvature in the direction-changing area, inorder to avoid damage to the glass fiber cables. Until now, in the sameway as when supplying cables via a shaft into a channel, it has beennecessary to partially remove the channel wall in the direction-changingarea or to allow a cable loop to project into the domestic channel line,resulting in the already mentioned disadvantages.

The present invention is therefore based on the object of avoiding thesedisadvantages and of providing a cable guide for a cable, in particulara glass fiber cable, in a direction-changing area, that is to say in anarea where a domestic channel line branches off from a main channel,which can be produced and installed in a simple manner and in which, inparticular, the existing channel wall need not be machined and is thusnot damaged or weakened either. Against the background of a cable guideon a channel mouth, having a guide tube which holds the cable in thearea of this channel mouth, the invention proposes that, in order toachieve this object, the guide tube be rigid, with the longitudinal axisof the guide tube being arranged along the envelope surface of acylinder at least in the central section which runs in thedirection-changing area, the axis of which cylinder runs in thelongitudinal direction of the channel mouth, and that that end area ofthe guide tube which is located in the channel mouth be connected to aflexile guide element, such as a flexible tube, a flexible pipe or thelike, which is known per se and holds the cable.

Since the cable is held by the rigid guide tube in thedirection-changing area, the cable is forced to adopt a specific profilecorresponding to the shape of this rigid guide tube in which case, sincethe central section of this rigid guide tube runs along the cylindricalenvelope surface in the form of a three-dimensional curve, this ensuresthat, on the one hand, the radius of curvature is not less than therequired minimum radius of curvature, while, on the other hand, thisavoids the cable and the guide tube and guide element which surround thecable from projecting into the main channel and into the channel mouth.The rigid guide tube is preferably shaped appropriately on a template inorder to comply with the conditions that have been mentioned. The cableis guided in the normal manner in the channel mouth in a guide elementwhich is formed by a flexible pipe, tube or the like and which must beconnected to the end of the rigid guide tube. For this purpose, the endof the guide element is, according to the invention, provided with apreferably integrally formed sleeve, which holds the end area of therigid guide tube.

A further important feature for the cable guide according to theinvention is the point at which the cable emerges from the rigid guidetube at its ends, because this should be a point located well away fromthe base of the channel system in order that the cable does not form anobstruction to the flow of the contaminated water. For this reason, itis advantageous for the central section of the rigid guide tube, whichruns essentially along a cylindrical envelope surface, to be attached toa pipe connecting stub, within said pipe connecting stub, which rests onthe wall of the channel mouth, that is to say of the domestic channelline. An optimum cable position is achieved if the rigid guide tube ispositioned in the pipe connecting stub such that its other end area runsapproximately at right angles to the longitudinal axis of the pipeconnecting stub, and preferably approximately tangentially with respectto the circumference of the pipe connecting stub, while, in contrast,the end area which is located in the channel mouth runs approximatelyparallel to the longitudinal axis of the pipe connecting stub. The pipeconnecting stub together with the rigid guide tube which is fixed in itcan in this case be positioned in the channel mouth such that the endareas of this guide tube assume the optimum position as mentioned. Inthis case, the pipe connecting stub can preferably be widenedelastically so that, after being inserted into the channel mouth, it ispressed by the elasticity against the channel wall, so that there is noneed for any additional measures for fixing the pipe connecting stub inthe required position. The pipe connecting stub is preferably formedfrom a metal sheet which is slotted in the axial direction and is curvedwith respect to the pipe connecting stub so as to ensure the requiredelastic expansion capability.

As already mentioned, the rigid guide tube is expediently bent to thedesired shape on a template, and it then retains this shape. The rigidguide tube may in this case be formed from plastic or from metal. Therigid guide tube is preferably, however, formed from a metal/plasticcomposite tube, which results in the advantage that this ensures that itcan be deformed easily, while the shape that has been formed issubsequently retained.

As already mentioned, the central section of the rigid guide tube isattached to the inner wall of the pipe connecting stub. Clamps, cableties or the like can be provided for this purpose on the inner wall ofthe pipe connecting stub.

A further requirement for the cable guide according to the invention isthat the guide element which holds the cable and is located in thechannel mouth, that is to say in the domestic channel line, is locatedin the area of the top of the domestic channel line, and thus does notimpede the flow of the sewage. Care must therefore be taken to ensurethat this guide element is fixed at the point that has been mentioned inthe domestic channel line, which generally has a maximum diameter of 500mm. A flexible cladding tube which rests on the wall of the channelmouth and fixes the guide element on this wall is provided for thispurpose adjacent to the pipe connecting stub. This flexible claddingtube may be impregnated with a synthetic resin, which can be cured,preferably by supplying heat. In this case, once the flexible claddingtube has been pressed against the wall of the channel mouth, theflexible tube is solidified by the curing of the synthetic resin and, inconsequence, the guide element is supported on the channel wall.

The method according to the invention for the production of a cableguide for a cable, in particular a glass fiber cable, which is guided ina channel system, preferably a sewage channel system, in thedirection-changing area on a channel mouth, consists in that a flexibleguide element, such as a flexible pipe, a flexible tube or the like,which originates from the direction-changing area is first of allinserted into the channel mouth, in that the end of this guide elementis connected to a rigid guide tube which has been deformed such that itslongitudinal axis in the central section runs essentially along animaginary cylindrical envelope surface, in that this rigid guide tubethen is fixed on the inside of a pipe connecting stub which can bewidened elastically, after which the pipe connecting stub is theninserted, with the rigid guide tube fixed to it, into the channel mouthfrom the direction-changing area such that the pipe connecting stubrests in a stressed manner on the wall of the channel mouth and therigid guide tube emerges from the pipe connecting stub into the channelsystem approximately tangentially in the area of the upper boundary ofthis pipe connecting stub, following which the cable is drawn into theguide tube and its guide element which is connected to it. This resultsin a cable guide being produced in a simple manner, in which the cableassumes the required position in the direction-changing area and, inparticular, is not unacceptably bent.

In a further method step, a flexible cladding tube is inserted throughthe pipe connecting stub into the channel mouth with the flexiblecladding tube being pressed against the wall of the channel mouth andagainst the guide element which runs along this wall, and being fixed inthis pressed-on position by supplying a pressure medium, preferablypressurized water, into the flexible tube interior. In consequence, theguide element is fixed in position in the channel system in the desiredmanner.

The flexible cladding tube which is impregnated with a synthetic resinthat can be cured, is fixed by supplying a heated medium, in particularheated water, into the flexible tube interior, thus resulting in thecuring process taking place, and the flexible tube being solidified.

BRIEF DESCRIPTION OF THE DRAWINGS

The cable guide according to the invention is illustrated schematicallyin the drawing.

FIG. 1 shows a horizontal section through a channel system;

FIG. 2 shows a section along the line II—II in FIG. 1;

FIG. 2 a shows a guide tube for holding the glass fiber cable, on adeveloped cylindrical envelope;

FIG. 3 shows a section along the line III—III in FIG. 1;

FIG. 3 a shows a modified embodiment corresponding to the illustrationin FIG. 3;

FIG. 4 shows a perspective illustration of the major component of thecable guide according to the invention;

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The sewage channel system that is illustrated in FIG. 1 has a mainchannel 1, from which a domestic channel line 2 branches off. A support,which is not illustrated, for the glass fiber cable that is passedthrough this main channel is located, for example, in an arch of themain channel 1, which has an egg-shaped cross section. A glass fibercable 3 is intended to be passed from this as a branch via the domesticchannel line 2 to a building that is located on a piece of land. Thebranch is produced via a distribution box 4 which is attached to thewall of the main channel 1.

As can be seen from FIG. 3, the glass fiber cable 3 is guided in a guideelement 5 which is formed from a tube, a flexible tube or the like andis arranged in the manner which will be described in more detail in thefollowing text at the top of the domestic channel line in order that thebase of this domestic channel line 2, which carries the sewage, is keptfree.

A rigid guide tube 7 for the glass fiber cable 3 is provided in thedirection-changing area 6, that is to say in that area where the glassfiber cable 3 coming from the main channel 1 opens into the domesticchannel line 2, and is connected in a liquid-tight manner at one of itsends to this guide element 5 via a sleeve 8 which is integrally formedon the guide element 5, and opens at its other end into the distributionbox 4. The central section 7′″ of the rigid guide tube 7 runsessentially along the envelope surface of a cylinder, and is thus shapedsuch that the glass fiber cable which is held by this guide tube 7 isnot subjected to any unacceptable kinking loads, and assumes the desiredposition with respect to the channel system. In order to secure thisposition, the rigid guide tube 7 is fixed on the inside of a pipeconnecting stub 10 via cable ties 11 or other attachment devices. Thepipe connecting stub 10 can be widened elastically and is formed from ametal sheet (see FIG. 4) which is slotted in the axial direction and iscurved such that, after being inserted into the domestic channel line 2,it rests on the channel wall in a stressed manner, and is thus fixed inits position. The pipe connecting stub 10 is inserted into the domesticchannel line 2 such that, as can be seen from FIGS. 2 and 4, one endarea 7′ of the rigid guide tube 7, which is connected to thedistribution box 4, runs approximately at right angles to thelongitudinal axis of the pipe connecting stub 10 and essentiallytangentially with respect to the circumference of the pipe connectingstub 10 while, in contrast, the other end area 7″, which is connected tothe guide element 5, emerges from the pipe connecting stub 10, in itstop area, approximately parallel to the longitudinal axis of this pipeconnecting stub 10.

The guide element 5 is fixed at the top of the domestic channel line 2in such a way that this guide element is first of all moved to thedesired position by means of suitable aids, after which a flexiblecladding tube 12, which is impregnated with a synthetic resin that canbe cured (see FIG. 3) is introduced via the pipe connecting stub 10 intothe domestic channel line 2. The flexible cladding tube 12 is introducedin such a way that one of its ends is closed in a sealed manner, andsuch that the flexible tube is filled with a pressure medium, preferablywater, so that the flexible tube is forced over and is pressed againstthe wall of the domestic channel line and against the guide element 5,assuming the position illustrated in FIG. 3. The flexible cladding tubeis then heated by supplying heated water to it, as a result of which thesynthetic resin is cured and the flexible cladding tube 12 issolidified. As can be seen from FIG. 3, the cross section of thedomestic channel line 2 is not reduced significantly during thisformation process, so that the outlet for the sewage is not impeded.

The process of drawing the glass fiber cable 3 into the rigid guide tube3 and into the guide element 5 which is adjacent to it is not carriedout until these parts have been installed and fixed.

FIG. 3 a shows an embodiment in which two guide elements 5 which runparallel are provided with glass fiber cables 3 located in them. Anembodiment such as this has the advantage over the arrangement of twoglass fiber cables in a single guide element 5 with a larger crosssection that this has a less adverse effect on the flow in the crosssection of the domestic channel line 2.

The expression a rigid guide tube 7 should also be understood as meaninga moulding which can be bent only with difficulty, for example a pieceof tubing composed of plastic which can be bent only with difficulty.

The guide tube 7 rests on the inner surface of the pipe connecting stub10 in the inner area of the pipe connecting stub 10.

The end area 7′ of the guide tube 7 can assume all the intermediatepositions between three preferred positions, as illustrated in FIGS. 2and 4.

The position and alignment of the end area 7′ and of the pipe connectingstub 10 in the domestic channel line 2 are matched during insertion ofthe pipe connecting stub 10 to the profile of the cables which havealready been laid, or are to be laid, in the main channel 1. The endarea 7′ advantageously runs horizontally and opens in the uppermost areaof the domestic channel line 2 into the pipe connecting stub 10; the endarea 7′ can also open into the domestic channel line 2 in the upper areaof the side wall of a domestic channel line.

In the area where it opens into the domestic channel line 2 or into thepipe connecting stub 10, the end area 7′ is curved in a plane at rightangles to the longitudinal axis of the pipe connecting stub 10 and/or ina plane which runs parallel to the axis of the main channel 1, andcontains the generatrix of the pipe connecting stub 10.

Within the pipe connecting stub 10, the guide element 5 in the guidetube runs essentially at the top of the pipe connecting stub 10 or ofthe domestic channel line 2. The connection to the end area 7″ is alsomade in this domestic channel line.

1. A cable guide for guiding a cable in a channel system having a mainchannel and a channel mouth, the cable guide comprising: a rigid guidetube holding the cable in a region of the channel mouth, said guide tubehaving a longitudinal axis extending, at least in a central segmentthereof, along a substantially cylindrical envelope surface defined withan axis running in a longitudinal direction of the channel mouth; and aflexible guide element connected to an end of said rigid guide tube inthe channel mouth and holding the cable in the channel mouth.
 2. Thecable guide according to claim 1, wherein the cable is a glass fibercable guided in a sewage channel system.
 3. The cable guide according toclaim 1, wherein said flexible element is a flexible tube or a flexiblepipe.
 4. The cable guide according to claim 1, which further comprises asleeve connecting said end of said rigid guide tube to said guideelement.
 5. The cable guide according to claim 4, wherein said sleeve isintegrally formed on said guide element.
 6. The cable guide according toclaim 1, which further comprises a pipe connecting stub resting on awall of the cable mouth, and wherein said central segment of said guidetube extending substantially along the cylindrical surface is attachedwithin said pipe connecting stub.
 7. The cable guide according to claim6, wherein said end of said rigid guide tube extends approximatelyperpendicularly to a longitudinal axis of said pipe connecting stub. 8.The cable guide according to claim 7, wherein said end of said rigidguide tube extends approximately tangentially with respect to aperiphery of said pipe connecting stub.
 9. The cable guide according toclaim 6, wherein a second end area of said rigid guide tube oppositesaid end runs approximately parallel to a longitudinal axis of said pipeconnecting stub.
 10. The cable guide according to claim 6, wherein saidpipe connecting stub is configured to be elastically widened.
 11. Thecable guide according to claim 6, wherein said pipe connecting stub isformed of a metal sheet slotted in an axial direction of said pipeconnecting stub.
 12. The cable guide according to claim 1, wherein saidrigid guide tube is a metal/plastic composite tube.
 13. The cable guideaccording to claim 1, which further comprises attachment devicesdisposed to attach said rigid guide tube on an inner wall of said pipeconnecting stub.
 14. The cable guide according to claim 13, wherein saidattachment devices include devices selected from the group consisting ofclamps and cable ties.
 15. The cable guide according to claim 1, whichcomprises a flexible cladding tube is disposed adjacent said pipeconnecting stub, said flexible cladding tube resting on wall of thechannel mouth and fixing said guide element thereon.
 16. The cable guideaccording to claim 15, wherein said flexible cladding tube isimpregnated with a curable plastic resin.
 17. The cable guide accordingto claim 15, wherein said flexible cladding tube is impregnated with aheat-curable plastic resin.
 18. A method for producing a cable guide fora cable to be guided in a channel system, the channel system having achannel extending in a given direction and a channel mouth defining adeflection area, the method which comprises: inserting a flexible guideelement originating from the direction-changing area into the channelmouth; connecting an end of the guide element to a rigid guide tubehaving been deformed such that a longitudinal axis in a central segmentthereof runs substantially along an imaginary cylindrical surface;fixing the rigid guide tube on an inside of a pipe connecting stub, andthen inserting the pipe connecting stub, with the rigid guide tubeaffixed, into the channel mouth from the direction-changing area suchthat the pipe connecting stub rests in a stressed manner on a wall ofthe channel mouth and the rigid guide tube emerges from the pipeconnecting stub into the channel system approximately tangentially at anupper boundary of the pipe connecting stub; and subsequently drawing thecable into the guide tube and the guide element connected thereto. 19.The method according to claim 18, which comprises fixing the rigid guidetube inside a pipe connecting stub configured to be widened elastically.20. The method according to claim 18, wherein the cable is a glass fibercable guided in a sewage channel system.
 21. The method according toclaim 18, wherein the guide element is a flexible pipe or a flexibletube.
 22. The method according to claim 18, which further comprisesinserting a flexible cladding tube through the pipe connecting stub intothe channel mouth, with the flexible cladding tube being pressed againstthe wall of the channel mouth and against the guide element runningalong the wall, and fixing the cladding tube in the pressed on positionby supplying a pressure medium into the flexible tube interior.
 23. Themethod according to claim 22, which comprises supplying pressurizedwater as the pressure medium.
 24. The method according to claim 22,wherein the flexible cladding tube is impregnated with a curablesynthetic resin, and the fixing step comprises supplying a heated mediuminto the flexible tube interior.
 25. The method according to claim 24,wherein the step of supplying a heated medium comprises pumping heatedwater into the flexible tube.